Diffuse Scattering of aged (U,Pu,Am)O2 single-crystals

Overview & Synopsis

Neutron diffuse scattering was used in order to study short range order in 20 years aged (U,Pu)O2 single-crystals. Since their fabrication[1] these samples had not undergone any thermal treatment, they thus contain both their original elements as well as radiogenic helium and an extra amount of Am due to 241Pu alpha-decay. The signal scattered between Bragg peaks contains information related to short-range order. These elements all show a diffusion length for neutrons which is of the same order of magnitude making it possible to study the contribution of the actinide cations, O2- anion and He. The diffraction study was carried out in Léon Brillouin Laboratory, on 5C2 beamline, with a four-circle diffractometer. This latter allows to determine crystal structures of single crystals. The 3D intensity map was fitted by means of DISCUS[2] software. References 1. J. Spirlet, E. Bednarczyk, I. Ray, W. Müller, Crystal growth of actinide dioxides by chemical transport, Journal de Physique 40 (1979) C4-108-110, DOI: 10.1051/jphyscol:1979434 2. Reinhard B. Neder and Thomas Proffen, Diffuse Scattering and Defect Structure Simulations,IUCr Texts on Crystallography, Vol 11, Oxford University Press, 2008